The Opportunities For Digital Surfacing - Part 2

More documents

Recommendations

Info

ADVERTISEMENT and jerk behavior in order to calculate the optimal feed rate for each individual lens. Once the designs are available to labs, the assumption must be made that the designer has confirmed that the design corrects eyesight in the way intended. Manufacturers have begun to license their design files through programs where they will assist in the correct transfer of the design through the lab for delivery to the ECP. For example, Essilor has begun Digital Surfacing Extended Offering (DEO). Beginning third quarter, the first independent laboratory will offer Varilux 360° as part of a turnkey package. With equipment specified by Essilor and with software to download instructions from an Essilor server, the designs will be transferred to the lab for manufacture.To ensure accuracy of design and patient satisfaction,sample control lenses are sent daily to Essilor for analysis and verification. Adjustments can be made in real time.To complete the delivery of premium vision in design, Crizal Alizé is also available to these labs. Process Integration – Like the doctor’s office that purchases a variety of instruments and then needs to add the test data to the patient’s record as part of an electronic medical record,instrument software is required to “talk”to practice management systems to increase office efficiency. Why enter patient name and data multiple times in an electronic record when an integration of the systems can do it The same is now possible for the lab so that electronic data systems transfer machine-operating instructions for the Rx needed by any bar coded tray. Who’s on board Visionstar,CC Systems and Digital Vision lab management systems support “connectivity”with some of the generator companies. Be sure to review system capability and implementation of the VCA communication protocol. Implementation – Each lab should expect the same learning curve when installing new equipment and new software digital surfacing with one major difference. When installing direct or digital surfacing, one should expect a higher level of support from the lens design source, lab management software company and equipment supplier since the integration of these tools is essential for success.In fact, it is the responsibility of the lens design source to initially ensure that the design is correct since that’s the license being secured. Milling Characteristics – In the past, the lab had to determine the materials that were most often ordered when choosing equipment. Today,the digital surfacing generator is capable of cutting all materials and polishing requires adjustment depending on material. For example, the high utilization of polycarbonate in the U.S. affects machine efficiency.The Schneider HSC generator series incorporates three major changes for polycarbonate. First, the milling tool cuts short chips which are easier to clear from the chamber. Next, the cutting tool is positioned upside down to take advantage of gravity.And last,the work space is inclined to enhance swarf removal. Standard sphere and toric curves are cut by polycrystalline diamond (PCD),complex curves (progressives) require natural diamond for the smoothest surface. Surface Protection and Blocking – Blocking and surface protection is the same as it is for standard surfacing i.e., there are material stresses created by pressure and temperature, specific to lens material. For example, a lens whose front surface is spherical to start, after blocking and generating may be correct in design after cutting but once removed from the block, incorrect in design.This has been the same for standard progressives when blocking alloy has been too hot, lenses weren’t allowed to cool sufficiently before generating or too small a diameter block used.The surface “warps” and the corridor may have become unusable yet the distance and near values were correct. In addition, the blocking tolerances for digital surfacing are tighter. Centering of the Optic - For lenses with engravings on the front, exact centering is required without blocking errors that might make the optics drift in position. Some believe that engraving after the lens is manufactured is better,it marks what you have done,not what you would like to have done.The other opportunity is to use digitally surfaced lenses that have front and back optics where a majority of the progressive surface is already on the front and the engravings have been applied to the mold prior to the casting process. Cutter Position and Data Feed – The maximum speed achieved for cutting with the precision required depends on the complexity of the surface. For complex surfaces,the maximum stroke,acccelleration and jerk of the motor sets minimum processing time limits. Polishing – How has the more difficult polishing process been developed and what are the attributes of well-polished lenses The surface has been prepared to be as smooth and near transparent as possible,however,the fineness of cut is not yet possible to just allow a coating to complete the lens. As a result, a slight buffing or polish is required.The Polishingconformable tools, variable paths. Twin tools, PCD and natural diamond. use of hard laps are not possible because those will destroy the surface shape, therefore soft and conformable tools have been developed to buff the surface.They adjust to the shape of the surface.In addition,different tool radii are used to best match the surface curves generated. Special oscillation and polishing paths help ensure that the surface created is well polished.As a result,the software developed to guide lens path over the tool and the tools chosen are different for each lens surface.The equipment software and lab management software work together to understand which lens is being worked on so the correct polishing is completed. What Are the Economics For small labs, purchase is difficult.There is the high capital outlay, from $500 thousand to $1 million dollars. Since the overall volume of digitally 2• Digital Surfacing
ADVERTISEMENT surfaced lenses is still low,for many it is difficult to justify the expense.As a result, many small labs are waiting until there is more trial, use and increased demand by ECPs before they purchase their own equipment. In the meantime,however,many already provide digitally surfaced lenses through larger labs with which they have relationships or special digitally equipped labs that act as labs’ labs. Regardless, ECPs can get a variety of lenses from a good number of their suppliers. Digitally surfaced lenses are available from many of the large and/or vertically integrated labs owned by lens manufacturers or large chains. For many of these companies, they have labs that are digitally capable in Europe and/or Asia and therefore have quite a bit of experience over the last 6-7 years. And, as we reported previously, customized progressives already account for 25 percent of the European progressive market in some sectors.Therefore, this application is well defined in Europe but as yet not in the US market. What Happens to Standard Sphere And Toric Production Any lab can cut standard spheres and toric backs on fixed design, front surface progressives, whether or not they have been created using digital surfacing. However, customized designs will have the lenses with specially cut backs. For lenses like Physio360, the back surface creates sphere or cylinder power, axis and the optimization of front peripheral stigmatism. So the surface is no longer a traditional sphere or toric back. The same is true of Definity which incorporates a portion of the add power on the back surface of the lens along with the necessary sphere or cylinder powers.The combination of the surface is defined mathematically and cut and polished to deliver both.For Varilux Ipseo,SOLAOne HD and Compact Ultra HD, the prescription and progressive is cut onto the back surface, the front being spherical.In both lenses,the manufacturers assume an average vertex and tilt to calculate the lens powers.For the Zeiss Gradal Individual,the lens is personalized using vertex and tilt measurements from the actual fitting. In the future,a variety of lenses will require additional measurements for personalization and a variety of tools will be available.For example,Carl Zeiss Vision introduced Eye Terminal at Vision Expo East,an instrument designed for the ECP for accurate and repeatable lens measurements. More about these devices in the next issue. What Happens to “Base Curve” Lenses will still have a recommended base curve and manufacturers will continue to supply base curve charts for reference. However, the option exists for back surface progressives to use a larger variety of base curves for the same prescription when trying to match the curve cosmetics of frames. So a -2.00 lens could be designed on a 4 base or an 8 base curve if used in a standard shape or in a wrap frame respectively. For the wrap frame, the Rx, add and the effects of the wrap angle can be optimized for a 7 or 8 base so that the central power incorporates the prism needed for good binocularity and peripheral optics are more usable by optimization. If you have questions about a particular job; call your lab or the manufacturer for details and explanatory literature. What Should be the ECP’s Expectation of the Lab Labs will continue to be the ECP’s best resource for information and recommendations for patients’ lenses. As they get more experienced, they will share more of the experiences of their customers and their customers’ “pearls”. Seek out those labs that have begun to offer digitally surfaced products for information and experiences—seek out peers that have begun to add digitally surfaced products to their portfolio of lenses.The overall reactions of the vast majority of patients and professionals trying the lenses are that they provide improved clarity of vision and a more comfortable wearing experience. For some it’s “wow,” for others the small improvements are noticeable and appreciated. Where’s the Liability of Design While there will be some variation,correctness of design now lies with the lens design originator and the producer of that design i.e., the lab supported by the design source. Of course, as in the standard supply chain, the ECP will hold the lab responsible, the lab will hold the manufacturer responsible, etc. How Does the Lab Ensure Equipment Calibration And Design Verification The lab will initially rely on the equipment supplier and their technicians for calibration and design verification until they are functional.Essilor will require audit lenses,others will create their own verification systems.Regardless,learn and understand how your source of digitally surfaced lenses ensures that the ECP receives the right product. For the lab, much of this new equipment is very robust i.e., self-calibrating with their own sets of controls and checks.New for the lab however,will be a requirement for increased knowledge about the technology.That will mean internal engineering staff capable of better understanding the integration of software with the technology of the equipment. In fact, this will open many new opportunities for lab staff as well as require the labs to source personnel with new skills.For some small labs,this may create some challenges. Some compare this shift to AR and its implementation in the lab. Like AR, the labs quickly embraced and began to offer products as they improved their capabilities.The difference here is that the manufacturer or source of the lens design is a partner with the lab.As a result,the power of the manufacturer and the reputation of their design require that they help ensure success. What Will the ECP do to Verify Lenses Lens verification for the ECP will be the same as it is now—verify distance and add power,fitting height and monocular PD’s well as base curve,lens materials and treatments.The rest is left up to the patient because the assumption is made that the design is correct. Since the manufacturers control the designs there should be audits of production and those that license designs have a responsibility to stop those products that don’t meet product design criteria. Digital Surfacing •3
Page 1: ADVERTISEMENT THE OPPORTUNITIES FOR

The Opportunities For Digital Surfacing - Part 2

Create successful ePaper yourself

Delete template?

Save as template?